Preheat your oven to 375°F (190°C). Gather your ingredients and prep your workspace.

Bring a large pot of salted water to a boil. Cook the jumbo pasta shells until al dente, about 10-12 minutes. Drain and rinse with cold water.

In a skillet, heat olive oil and sauté minced garlic for 1-2 minutes until fragrant. Remove from heat and allow to cool.

In a bowl, combine ricotta cheese, squeezed spinach, grated Parmesan, egg, salt, pepper, sautéed garlic, and basil. Mix until smooth.

Spread 1 cup of marinara sauce in a 9x13-inch baking dish. Stuff each shell with about 2 tablespoons of filling and place them open side up.

Pour remaining marinara sauce over the shells and sprinkle with mozzarella cheese.

Cover the dish with foil and bake for 20 minutes. Remove the foil and bake for an additional 10 minutes until cheese is golden.

Let the dish rest for 5 minutes before serving. Spoon extra sauce over each serving.